Centrifugal filters



May 14, 1957 W. H. TAIT CENTRIFUGAL FILTERS 2 Shoots-Sheet 2 Filed Feb. 25, 1954 by M CENTRIFUGAL FILTERS William Henry Tait, Alperton, Wembley, England, assignor to The Glacier Metal Company Limited, Alperton, Wembley, England, a British company This invention relates to centrifugal filters, and is particularly concerned with a centrifugal filter for cleaning lubricating oil and fuel oil in internal combustion engine installations.

Various forms of centrifugal filters driven mechanically by an external source of power have been proposed but for simplicity and ease of installation contrifugal filters in which the centrifuge bowl is rotated by a coaxial reaction jet engine unit are to be preferred. The reaction jet engine unit usually comprises a tangentially directed nozzle or nozzles associated with the centrifuge bowl and receiving clean liquid under pressure therefrom.

Centrifugal filters of the reaction jet type are particularly suitable for cleaning lubricating oil supplied under pressure from the service pump of an engine installation, inasmuch as the centrifugal filter can be included in a by-pass circuit ensuring adequate flow to the reaction jets as all times for attaining and maintaining the requisite speed of rotation of the centrifuge bowl for effective separation of dirt particles, irrespective of the rate at which the lubricating oil is supplied to the engine bearings.

In the case of fuel oil, however, by-pass operation of a centrifugal filter is unsuitable because it is desirable that the fuel oil should be subject to filtration in the course of its passage from a supply to the point of consumption. The rate of flow of the fuel oil determined by its consumption is restricted and generally would be insufficient for the purpose of driving the centrifuge bowl by reaction jets. Furthermore, in the case of fuel oil it is especially desirable that the oil should remain in the centrifuge bowl as long as possible to ensure removal of the finest dirt particles.

The present invention has for its object to provide an improved construction of centrifugal filter whereby effective cleaning of both lubricating oil and fuel oil my be effected by the use of a reaction jet driven centrifuge bowl unit .or assemblage.

According to the present invention, a centrifugal filter for cleaning lubricating oil and fuel oil in internal combustion engine installations comprises a centrifugal lubricating oil filter having a reaction jet driven centrifuge bowl and a centrifugal fuel oil filter having a centrifuge bowl and driven from the centrifuge bowl of the lubricating oil filter. Preferably the centrifugal filter comprises two centrifuge bowls mounted to rotate in separate compartments of a common casing, one centrifuge bowl to which lubricating oil is supplied under pressure communicating with reaction jet nozzles discharging into the respective compartment and thence to a drainage outlet, while the other centrifuge bowl is driven with or rotated by the first-mentioned bowl and is adapted for centrifugal cleaning of fuel oil.

In one embodiment a substantially cylindrical casing may be divided into upper and lower compartments by means of a transverse partition of non-magnetic material adapted to hermetically seal the compartments from one another, the lubricating oil centrifuge bowl and the fuel tes Patent Patented May 14, 1957 oil centrifuge bowl being mounted in the compartments to rotate about a common vertical axis and drive from the lubricating oil centrifuge to the fuel oil centrifuge is transmitted by magnetic means without any direct driving means extending through the said partition. The magnetic means may comprise a magnet or a number of magnets mounted on one centrifuge bowl to revolve about the axis of the bowl in a path close to one side of the said transverse partition to coact with other magnets or elements of ferro-magnetic material similarly mounted and arranged on the other centrifuge bowl close to the other side of said partition. The fuel oil centrifuge bowl may be disposed in the upper compartment which is provided with a drainage outlet at the bottom for carrying away any fuel oil leaking from the respective bowl. The fuel oil may be introduced into the respective centrifuge bowl through an axial passage in a central spindle communicating with the centrifuge bowl at its lower part, clean fuel oil being withdrawn from the bowl through a coaxial outlet at its upper part.

Lubricating oil under pressure may be introduced into the upper part of the centrifuge bowl through an axial passage in a central spindle, and said bowl may be provided at its lower part with a reaction jet nozzle or nozzles discharging into the respective compartment having at its lower part a lubricating oil discharge outlet.

In a further embodiment, the two centrifuge bowls for lubricating oil and fuel oil may be fixedly mounted on a common vertical spindle which extends through a transverse partition dividing the casing into upper and lower compartments, the centrifuge bowl in the upper compartment receiving lubricating oil under pressure through an axial inlet in the spindle, and having a reaction jet nozzle or nozzles at its upper part discharging into an outer zone of the upper compartment which at its lower part communicates with a lubricating oil outlet, while the centrifuge bowl in the lower compartment receives fuel oil through an axial inlet in said spindle. A cylindrical bafile preferably extends upwardly from said partition to surround the lubricating oil centrifuge bowl and is flanged inwardly at the top to extend close to said bowl below the reaction jet nozzle or nozzles, and said partition is of domed formation and flanged upwardly at the centre to surround an intermediate part of the spindle for the purpose of avoiding leakage of lubricating oil from the upper compartment to the lower compartment. Leakage oil collected by the baffles may pass through an aperture or apertures in the lower part of the cylindrical baffle to the lubricating oil outlet. The fuel oil centrifuge bowl in the lower compartment discharges into the said compartment which is provided at its lower part with an outlet from which fuel oil is withdrawn by gravity for use, and a float in a lower part of said lower compartment is arranged to operate a valve member controlling supply of fuel oil to the centrifuge bowl.

The lubricating oil centrifuge bowl may be provided with a transverse partition separating a main part of the bowl from a chamber communicating with the reaction jet nozzle or nozzles, said chamber communicating with the main part f the bowl through a standpipe arrangement which may be coaxial with the bowl and extends towards the inlet end thereof from the partition separating the main part of the bowl from said chamber.

The fuel oil centrifuge bowl may be provided with an inner bowl, an annular space between the inner and outer bowls communicating at one end with the fuel oil inlet and at the other end with the interior of the inner bowl which, in turn, communicates with a coaxial outlet adjacent the spindle carrying the bowl. When the fuel oil centrifuge bowl is mounted in the lower compartment of the casing, the coaxial outlet passage of the bowl may be formed by an annulus communicating with the upper part of the inner bowl which communicates through open ings in the lower part of its wall with the annulus between the inner and outer bowls, the tops of the bowls being spaced apart to provide a radial passage from the fuel oil inlet passage to the said annular space, and the outlet passage formed by said annulus having openings discharging into said lower compartment.

The invention is hereinafter described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

Fig. 1 is a sectional elevation illustrating one embodiment of centrifugal filter according to the invention; and

Fig. 2 is a similar view illustrating a modification.

In carrying the invention into effect according to one embodiment and with reference to Fig. l of the accompanying diagrammatic drawings, a substantially cylindrical casing constituted by upper and lower parts 1, 2 respectively is divided to provide upper and lower compartments 3, 4 by means of a transverse partition 5 of nonmagnetic material, such as a suitable plastic or stainless steel. The transverse partition 5 is suitably flanged at its periphery so that it may be clamped between flanges 6, 7 of the respective upper and lower parts 1, 2 of the casing which are connected together by means such as bolts of which only one, 8, is shown in the drawing, the said bolts also serving to secure a removable closure member 9 for the upper compartment 3. The transverse partition 5 is formed with a centrally disposed upwardly projecting socket 10 which serves for the location of juxtaposed ends of upper and lower coaxial spindles 11, 12 respectively about which centrifuge bowls 13, 14 respectively rotate.

The bowl 14 in the lower compartment 4 is of the re action jet driven type and is supplied with lubricating oil under pressure from an inlet 15 through an axial passage 16 in the spindle 12 and radial outlets 17 communicating with the upper part of the bowl 14. Lubricating oil which has been subjected to centrifugal separation of dirt particles in the bowl 14 flows radially inwards and through a standpipe arrangement which may be constituted by a coaxial annulus 18 projecting from the discharge end of the bowl towards the inlet end thereof, to a chamber 19 formed by a bottom closure plate 20 in conjunction with a transverse partition 21 carrying the annulus 18, the bottom closure 20 being provided with one or more reaction jet nozzles 22. The bottom closure 20 provided with the nozzle or nozzles 22 and the transverse partition 21 carrying the annulus 18 preferably are removably held to the bowl 14 by means such as bolts 23 and constitute a reaction jet engine unit receiving clean lubricating oil from the bowl and driving said bowl at a. suitable speed, the nozzle or nozzles 22 discharging into the compartment 4 which is provided at the bottom with an outlet 42. A suitable sealing element 24 may be provided as shown. The bowl 14 is provided at the top and bottom with brushes 25 which are rotatable on the spindle 12.

The centrifuge bowl 13 in the upper compartment 3 receives fuel oil from an inlet 26 and through an axial passage 27 in the spindle 11, the axial passage 27 communicating with the lower part of the bowl 13 through radial passages 28. Preferably an inner bowl 29 is provided in the bowl 13, for example as shown, so that fuel oil introduced through the radial passages 28 flows radial ly outwards between spaced bottoms of the inner and outer bowls and then upwardly through the annular space 30 between the inner and outer bowls wherein the fuel oil is subjected to intensive centrifugal action for separation of dirt particles. The fuel oil then flows radially inwards through perforations 31 in the wall of the inner bowl 29 and thence to a coaxial outlet 32. The inner bowl 29 and a top closure 33 may be held to the bowl 13 by means such as bolts 34, of which one only is shown,

a suitable sealing element 35 being provided at the periphery of the interengaging parts. Any fuel oil which may leak into the compartment 3 past the lower bearing 36 and the upper bearing 38 carrying the bowl 13 may be led away through a drainage outlet 37. The bearing 38 supporting the upper end of the bowl 13 rotates on an annulus 39 defining the outlet 32.

The object of hermetically sealing the compartments 3, 4 from one another by means of the partition 5 is to prevent any possibility of lubricating oil becoming contaminated with fuel oil or vice versa.

The centrifuge bowl 13 is driven from the centrifuge bowl 14 by magnetic means which may comprise one or more permanent magnets 40 fixed by any suitable means to the top of the bowl 14 so as to revolve close to the underside of the partition 5 and to coact with similar permanent magnets 41 or elements of ferro-magnetic material similarly mounted on the underside of the bowl 13 to extend close to the upper side of the partition 5. The partition 5 preferably has a high electrical resistance and the magnets 40, 41 are mounted with magnetic insulation.

In the modification illustrated in Fig. 2, the casing constituted by the parts 1, 2 and top closure member 9 may be constructed in a similar manner in parts held together by bolts 8, but in this arrangement the upper compartment 3 houses the lubricating oil centrifuge bowl 14 and the lower compartment 4, the fuel oil centrifuge bowl 13, the two bowls 13, 14 being also inverted from the positions shown in Fig. 1. The two centrifuge bowls 13, 14 are fixedly mounted on a common rotatable spindle 43 and the lower part 2 of the casing is provided at the bottom with a sump 44 leading to a fuel oil outlet 45. An intermediate part of the spindle 43 extends through a transverse partition 46 of domed formation having a peripheral flange 47 clamped between the upper and lower parts 1, 2 of the casing and having an upwardly extending flange 48 closely surrounding the intermediate part of the spindle 43, the partition 46 forming a baifle for preventing leakage of lubricating oil from the upper compartment 3 to the lower compartment 4. A cylindrical baffie member 49 having a peripheral flange 50 lying against the flange 47 and likewise clamped between the parts 1 and 2, extends upwardly to surround the bowl 14 and at its upper end is provided with an inwardly directed flange 51 which is below the level of the nozzle or nozzles 22 and extends close to the wall of the bowl 14 so that lubricating oil discharged from the nozzle or nozzles 22 into the upper part of the compartment 3 is directed to the lubricating oil outlet 42 at the lower part of the compartment 3. Openings 52 may be provided at the lower end of the baflle member 49 so that leakage oil collected by the battle arrangement may flow to the outlet 42.

Lubricating oil introduced through the inlet 15 flows through the axial passage 16 in the spindle 43 to radial passages 17 communicating with the lower part of the bowl 14. Fuel oil introduced through the inlet 26 flows upwardly through the axial passage 27 in the spindle 43 and is introduced into the upper part of the bowl 13 through the radial passages 28. As in the previous construction, an inner bowl 29 is placed within the outer bowl 13 so that the fuel oil passing through the radial passages 28 flows outwardly between the axially spaced parts of the bowls 13, 29 to the annular space 30 wherein it is subject to intensive centrifugal action for the separation of dirt particles while flowing downwards towards openings 31 in the lower part of the inner bowl 29. In order to avoid possibility of flooding of the lower part of the casing during periods of rest, the closure member 33 of the bowl 13 is preferably formed with an upwardly extending annulus 34 which defines a coaxial outlet passage 53 which communicates with the lower part of the compartment 4 through openings 54 and an intermediate annulus 55 through which the fuel oil flows upwardly from the openings 31 to the outlet passage 53.

Fuel oil may be fedaby gravity from the outlet 45 to the point of consumption and in order to regulate the supply of fuel oil through the inlet 26, a float 56 may be arranged in the sump 44 to operate a valve member 57 controlling the inlet 26, the valve member 57 being sealed by a suitable flexible bellows 58 or similar device.

It will be appreciated that in this embodiment it is preferred to arrange the lubricating oil centrifuge bowl in the upper compartment as-it is more important to avoid contamination of the lubricating oil with fuel oil.

The lubricating oil and fuel oil centrifuges are preferably constructed as shown of detachably connected sheet metal parts held together by bolts or the like, and this construction forms no part of the present invention.

It will be understood that the invention is not limited to the particular embodiments hereinbefore described. For example, the lubricating oil and fuel oil centrifuge bowls may be otherwise suitably arranged in separate compartments and any other suitable means may be provided for transmitting drive from the lubricating oil centrifuge bowl to the fuel oil centrifuge bowl. Furthermore, the lubricating oil centrifuge bowl may be driven by a reaction jet engine unit not necessarily forming part of the bowl but preferably supplied with clean oil from the bowl.

I claim:

1. A centrifugal filter for cleaning lubricating oil and fuel oil in internal combustion engine installations, comprising a centrifugal lubricating oil filter having a closed centrifuge bowl, an inlet to said bowl communicating with an external source of lubricating oil under pressure, reaction jet means for the discharge of lubricating oil under pressure from said bowl whereby said bowl is rotated, a centrifugal fuel oil filter having a centrifuge bowl, means for supplying fuel oil to said centrifuge bowl of said fuel oil filter, and drive means whereby the centrifuge bowl of the fuel oil filter is driven from the centrifuge bowl of the lubricating oil filter.

2. A centrifugal filter for cleaning lubricating oil and fuel oil in internal combustion engine installations comprising a casing having two compartments, a centrifuge bowl mounted to rotate in each of said compartments, means for supplying lubricating oil under pressure from an external source to the first of said bowls, reaction jet means on said first bowl whereby lubricating oil discharging therefrom into the compartment in which it is mounted causes said first bowl to rotate, means for supplying fuel oil into the second of said bowls and drive means whereby rotation of said first bowl causes rotation of said second bowl.

3. A centrifugal filter as defined in claim 2 in which the casing comprises a substantially vertically disposed cylindrical side wall and a substantially horizontally disposed transverse partition of non-magnetic material separating said compartments and in which the axes of rotation of said bowls are substantially vertically disposed and coincide and in which said drive means is magnetic and operates through said partition.

4. A centrifugal filter as defined in claim 3 in which said magnetic means comprises a magnet mounted on one of said centrifuge bowls adjacent to said partition and a magnetic element mounted on the other of said centrifugal bowls adjacent to said partition.

5. A centrifugal filter as defined in claim 3 in which the second of said bowls is located in the upper of said two compartments and said upper compartment is provided with a drainage outlet.

6. A centrifugal filter as defined in claim 3 in which the means for supplying fuel oil to said second bowl comprises an axial spindle on which said-second bowl rotates, a passageway in said spindle, an opening connecting said passageway with the interior of said bowl adjacent the lower end thereof and a coaxial outlet for clean fuel oil connecting the interior of said second bowl with the space outside of said casing.

7-. A centrifugal filter as defined in claim 5 in which the first of said bowls is located in the lower of said two compartments and in which said means for supplying lubricating oil to said first bowl comprises an axial spindle upon which said first bowl rotates, an axial passageway in said spindle and an opening through said spindle adjacent the upper end thereof connecting said passageway with the interior of said first bowl and in which said reaction jet means comprises a jet nozzle connecting the interior of said first bowl adjacent the lower end thereof with the space within said casing, and in which the lower of said two compartments has a lubricating oil outlet adjacent the lower end thereof.

8. A centrifugal filter for cleaning lubricating oil and fuel oil in internal combustion engine installations comprising a substantially vertically disposed casing, a substantially horizontal partition dividing said casing into an upper compartment and a lower compartment, a substantially vertically disposed spindle extending through said partition into said compartments, a centrifuge bowl rotatably mounted on said spindle in each of said compartments, an axial inlet in the upper end of said spindle, means for supplying lubricating oil under pressure from an external source to the centrifuge bowl in the upper compartment through said axial inlet, a reaction jet nozzle carried by the bowl in said upper compartment and discharging into said upper compartment, a discharge outlet for lubricating oil adjacent the lower end of said upper compartment, an axial inlet in the lower end of said spindle, means for supplying fuel oil from an external source to the centrifugal bowl in said lower compartment through said last named axial inlet and means whereby rotation of the bowl in said upper compartment causes rotation of the bowl in said lower compartment.

9. A centrifugal filter as defined in claim 8 comprising a cylindrical bafile extending upwardly from said partition and surrounding the centrifuge bowl in said upper compartment, a flange extending inwardly from the upper end of said battle with its inner edge close to said bowl at a level below the level of said reaction jet nozzle, said partition being dome-shaped and flanged upwardly around said spindle.

10. A centrifugal filter as defined in claim 9 in which said bafile is provided adjacent its lower edge with an opening for delivering oil to said discharge outlet.

11. A centrifugal filter as defined in claim 8 comprising a discharge outlet from the bowl in said lower compartment into said lower compartment, an outlet from said lower compartment, a valve controlling the supply of fuel oil to the axial inlet in the lower end of said spindle, and a float in said lower compartment in the path of the fuel oil flowing from the discharge outlet from said bowl to the outlet from said lower compartment, said float controlling the operation of said valve.

12. A centrifugal filter as defined in claim 2 in which said reaction jet means is located adjacent one end of said first bowl and said means for supplying lubricating oil to said first bowl has an inlet adjacent the other end of the bowl, a transverse partition in said first bowl between said jet means and said inlet and a standpipe extending from said partition toward said inlet.

13. A centrifugal filter as defined in claim 2 in which the second of said bowls has spaced apart inner and outer walls defining an annular space therebetween and a space within said inner wall and in which the means for supplying fuel oil communicates with one end of said annu lar space and the other end of said annular space cornmunicates with said space within the inner wall, and a coaxial fuel oil outlet communicating with said space within said inner wall.

14. A centrifugal filter for cleaning lubricating oil and fuel oil in internal combustion engine installations comprising a substantially vertically disposed cylindrical casing, a substantially horizontal partition wall dividing the 7 space within said easing into an upper and a lower compartment, an axially disposed spindle extending through said partition wall into said upper and lower compartments, 9. first centrifugal bowl rotatablymounted on said spindle in said upper compartment, means for delivering lubricating oil from an external source under pressure into said first centrifugal bowl, reaction jet means for discharging lubricating oil from said first centrifugal bowl, a lubricating oil outlet from said upper compartment, a second centrifugal bowl in said lower compartment, said second centrifugal bowl comprising an outer wall extending outwardly from said spindle and downwardly parallel to but spaced apart from said cylindrical casing, an inner wall extending outwardly from said spindle and downwardly parallel to said cylindrical casing and spaced apart from said outer wall, means for supplying fuel oil to the space between said inner and outer walls adjacent to said spindle, a closure member closing the lower end of the space between said inner and outer walls and also the lower end of the space between said inner wall and said spindle, said closure member having an upwardly extending annulus which is spaced apart from said inner walls and from said spindle thereby defining an annularspace which extends upwardly betweensaid inner wall and said annulus and downwardly between said annulus and said spindle, an opening adjacent the lower edge of said inner wall providing communication between the spacebetween said inner and outer walls, said annular space and an opening in said closure member adjacent to said spindle establishing communication between said annular space and said casing and means whereby rotation of said bowl in said upper compartment causes rotation of said bowl in said lower compartment.

References Cited in the file of this patent UNITED STATES PATENTS 

